Schist
Reference articles are in English.
A quartz–muscovite schist specimen showing its foliated structure. Source
Description
Schist is a metamorphic rock with visibly aligned minerals. Mica flakes may produce a sheen, while mineral bands and folds give it a directional appearance. Grey, silvery, greenish and brown varieties occur. The orientation of its layers is important in walling, placement and carving.
History
Heat, pressure and deformation align minerals as schist develops. The layers and folds visible in a finished piece record that geological history. Cutting across or along the foliation exposes different aspects of the structure.
Commissioning
The selected block should be reviewed with the maker for its soundness, visible faces and intended support. The brief should identify the orientation and finish. Thin areas and exposed edges require consideration of the actual layered stone.